There is a growing need to stabilize, protect and control the release of various substances, such as active ingredients that may be unstable, hydrophobic, volatile and/or toxic at high concentrations or sensitive to breakdown in different environmental conditions. Many of these active ingredients have useful or beneficial effects, for example, the anti-aging and anti-acne effects of retinol, which is used in formulations primarily intended for cosmetic use. For topical applications, retinol is typically formulated into creams, ointments, oils and the like. In such formulations, however, retinol can rapidly degrade and lose activity. In addition, moderate to severe skin irritation frequently results from the use of the formulations with retinol at high concentrations. This irritation is due to poor control over the dosage and delivery of the active ingredient. Similar problems exist for active ingredients used in dermatology to treat various skin diseases. For example, corticosteroids used to treat psoriasis can be challenging to formulate and deliver over time, causing the end user to apply a formulation multiple times per day, which can result in adverse side effects.
Accordingly, formulations are necessary to efficaciously deliver compositions including active ingredients in creams, lotions, powders, ointments and the like. However, such compositions that include the active ingredients are often difficult to formulate. Therefore, highly complex and intricate encapsulation methods have been developed to incorporate these substances into final product formulations. As an example, many delivery systems in the dermatological or personal care space use a core-shell encapsulation approach. However, this approach results in compositions that release their payload in the form of a bolus. Other existing solutions utilize highly complex, multi-stage processes to encapsulate the active ingredients that are difficult to scale in a technologically feasible or economically viable fashion.
For the foregoing reasons, there remains a need for an encapsulation material and a method for encapsulating active ingredients for use in controlled-release compositions and systems. The encapsulating material should improve the overall stability of the active ingredient, while effectively functioning as a vehicle to deliver active ingredients to a substrate without adversely affecting the chemical and physical properties of the active ingredients (i.e., to prevent the active ingredients from degradation). Ideally, the material and method will provide a system for encapsulating the particulate components for topical compositions for application to a substrate, such as the skin of a human or animal. The properties of the encapsulating material should be tunable so that, for example, the density, compressibility, size, size distribution and crosslink density are precisely controlled to provide the proper protection and release performance for a given application. Finally, the encapsulating material should be readily scalable to produce large quantities of material in a convenient and cost-effective manner.